The present invention relates to compositions, from which radically initiated oligomers/polymers having a controlled molecular weight, low polydispersity and a vinyl or dienyl end group can be prepared. Further subjects of the invention are a process for controlled radical polymerization, oligomers/polymers obtainable by said process and the use of specific addition fragmentation agents for the polymerization process. The addition fragmentation agents are new in part and these are also subject of the present invention.
Polymers of limited molecular weight, or oligomers, are useful as precursors in the manufacture of other polymeric materials and as additives in plastics, elastomers and surface coating compositions, as well as being useful in their own right in many applications.
In conventional polymerization practice, the manufacture of oligomers requires the use of an initiator which acts as free radical source and of a chain transfer agent. The chain transfer agent controls the molecular weight of the polymer molecule by reacting with the propagating polymer chain. At least a part of the transfer agent is incorporated into the polymer and thus is consumed during the process. The incorporated residue of the chain transfer agent can lead to undesirable end-groups on the polymer. Common chain transfer agents are for example alkanethiols, which cause an objectionable odour.
To avoid these deficiencies WO 88/04304 suggests nonionic acrylate or styrene derivatives as chain transfer agents for controlled radical polymerization.
The use of addition fragmentation agents to control molecular weight is known and a variety of compounds have already been suggested as for example described by Colombani et al. in xe2x80x9cAddition Fragmentation Processes in Free Radical Polymerizationxe2x80x9d, Prog. Polym. Sci., Vol. 21, 439-503, 1996. However there is still a need to provide easily accessible compounds which are highly efficient in thermally and in photochemically induced radical polymerization.
Y. Yagci et al. in J. Polym. Sci., Part A, Polym. Chem. Vol. 34, 3621-3624 (1996) disclose the use of allyl onium salts, in particular pyridinium salts, together with radical initiators for cationic polymerization.
Surprisingly it has been found that specific allyl or dienyl cationic systems are highly efficient addition fragmentation agents, useful for the control of molecular weight build up of radical polymerizations. The chain transfer coefficient cx is in many cases close to the theoretically ideal value of 1. Polydispersity of the oligomers/polymers is generally small and in many cases below 2. The compounds are easily accessible thus being ideally suitable for industrial applications.
These polymerization processes will also control the physical properties of the resulting polymers such as viscosity, hardness, gel content, processability, clarity, high gloss, durability, and the like.
The polymerization processes and resin products of the present invention are useful in many applications, including a variety of specialty applications, such as for the preparation of block copolymers which are useful as compatibilizing agents for polymer blends, or dispersing agents for coating systems or for the preparation of narrow molecular weight resins or oligomers for use in coating technologies and thermoplastic films or as toner resins and liquid immersion development ink resins or ink additives used for electrophotographic imaging processes.
One object of the present invention is a composition comprising
a) at least one ethylenically unsaturated monomer or oligomer
b) at least one radical initiator which forms a radical upon heating or upon irradiation with (UV) light from 305 nm to 450 nm and
c) a compound of formula (Ia), (Ib) or (Ic) 
Y is a group which activates the double bond towards Michael addition;
X is halogen or the anion of a mono carboxylic acid from 1-12 carbon atoms, a monovalent oxo acid or complex acid;
n is 0 or 1;
R1, R2, R3 are independently of each other hydrogen, unsubstituted C1-C18alkyl, C3-C18alkyl, interrupted by at least one nitrogen or oxygen atom, C3-C18alkenyl, C3-C18alkynyl, C7-C9phenylalkyl, C3-C12cycloalkyl or C3-C12cycloalkyl containing at least one nitrogen or oxygen atom; or
C1-C18alkyl or C3-C18alkyl interrupted by at least one nitrogen or oxygen atom, C3-C18alkenyl, C3-C18alkynyl, C7-C9phenylalkyl, C3-C12cycloalkyl or C3-C12cycloalkyl containing at least one nitrogen or oxygen atom, which are substituted by NO2, halogen, amino, hydroxy, cyano, carboxy, C1-C4alkoxy, C1-C4alkylthio, C1-C4alkylamino, di(C1-C4alkyl)amino or by a group xe2x80x94Oxe2x80x94C(O)xe2x80x94C1-C18alkyl; or
phenyl, naphthyl, which are unsubstituted or substituted by C1-C4alkyl, C1-C4alkoxy, C1-C4alkylthio, halogen, cyano, hydroxy, carboxy, C1-C4alkylamino or di(C1-C4alkyl)amino; or
R1 and R2, together with the linking hetero atom, form a C3-C12heterocycloalkyl radical; or
R1 and R2 form a group, 
xe2x80x83or
R1, R2 and R3 form a group 
Halogen is fluorine, chlorine, bromine or iodine, preferably chlorine or bromine.
The alkyl radicals in the various substituents may be linear or branched. Examples of alkyl containing 1 to 18 carbon atoms are methyl, ethyl, propyl, isopropyl, butyl, 2-butyl, isobutyl, t-butyl, pentyl, 2-pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, t-octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, hexadecyl and octadecyl.
Alkenyl with 3 to 18 carbon atoms is a linear or branched radical as for example propenyl, 2-butenyl, 3-butenyl, isobutenyl, n-2,4-pentadienyl, 3-methyl-2-butenyl, n-2-octenyl, n-2-dodecenyl, iso-dodecenyl, oleyl, n-2-octadecenyl oder n-4-octadecenyl. Preferred is alkenyl with 3 bis 12, particularly preferred with 3 to 6 carbon atoms.
Alkinyl with 3 to 18 is a linear or branched radical as for example propinyl (xe2x80x94CH2xe2x80x94Cxe2x89xa1CH), 2-butinyl, 3-butinyl, n-2-octinyl, oder n-2-octadecinyl. Preferred is alkinyl with 3 to 12, particularly preferred with 3 to 6 carbon atoms.
C3-C12cycloalkyl is typically, cyclopropyl, cyclobutyl, cyclopentyl, methylcyclopentyl, dimethylcyclopentyl, cyclohexyl, methylcyclohexyl.
Cycloalkyl which is interrupted by at least one O or N atom is for example 2-tetrahydropyran-yl, tetrahydrofurane-yl, 1,4 dioxan-yl, pyrrolidin-yl, tetrahydrothiophen-yl, pyrazolidin-yl, imidazolidin-yl, butyrolactone-yl, caprolactame-yl.
C7-C9phenylalkyl is for example benzyl, phenylethyl or phenylpropyl.
C3-C18alkyl interrupted by at least one O atom is for example xe2x80x94CH2xe2x80x94CH2xe2x80x94Oxe2x80x94CH2xe2x80x94CH3, xe2x80x94CH2xe2x80x94CH2xe2x80x94Oxe2x80x94CH3 or xe2x80x94CH2xe2x80x94CH2xe2x80x94Oxe2x80x94CH2xe2x80x94CH2xe2x80x94CH2xe2x80x94Oxe2x80x94CH2xe2x80x94CH3. It is preferably derived from polyethlene glycol. A general description is xe2x80x94((CH2)axe2x80x94O)bxe2x80x94H/CH3, wherein a is a number from 1 to 6 and b is a number from 2 to 10.
Y may be any substituent which facilitates Michael addition at the double bond. Preferably Y is CN, C(O)halogen, COOR4, C(O)R4, CONR5R6, phenyl or naphthyl which are unsubstituted or substituted by C1-C4alkyl, C1-C4alkoxy, C1-C4alkylthio, halogen, nitro, cyano, hydroxy, carboxy, C1-C4alkylamino or di(C1-C4alkyl)amino; and R4, R5 and R6 are hydrogen or C1-C18alkyl.
More preferably Y is CN, COOR4 or phenyl which is unsubstituted or substituted by C1-C4alkyl, C1-C4alkoxy, C1-C4alkylthio, halogen, cyano, hydroxy, carboxy, C1-C4alkylamino or di(C1-C4alkyl)amino; and R4 is C1-C4alkyl.
Most preferably Y is CN, COOCH3, COOC2H5 or phenyl.
X is halogen or the anion of a mono carboxylic acid from 1-12 carbon atoms, a monovalent oxo acid or complex acid.
Examples of monocarboxylic acids with 1 to 12 carbon atoms are formic acid, acetic acid, propionic acid, phenyl acetic acid, cyclohexane carbonic acid, mono-, di- and trichlor-acetic acid or mono-, di- and trifluor-acetic acid. Other suitable acids are benzoic acid, chlorbenzoic acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, chlorbenzenesulfonic acid, trifluormethanesulfonic acid, methylphosphonic acid or phenylphosphonic acid.
Preferably X is xe2x80x94Cl, xe2x80x94Br, xe2x80x94I, ClO4xe2x88x92, CF3SO3xe2x88x92, CH3SO3xe2x88x92, HSO4xe2x88x92, BF4xe2x88x92, B(Phenyl)4xe2x88x92, PF6xe2x88x92, SbCl6xe2x88x92, AsF6xe2x88x92 or SbF6xe2x88x92.
Further suitable anions are derived from alkyl-aryl-borates which are disclosed for example in U.S. Pat. No. 4,772,530, GB 2307474, GB 2307473, GB 2307472, EP 775706. Examples are triphenylbutylborate, triphenylhexylborate, triphenylmethylborate, dimesityl-phenyl-methyl- or -butylborate, di(bromomesityl)-phenyl-methyl- or -butylborate, tris(3-fluorphenyl)-hexylborate, tris(3-fluorphenyl)-methyl- or -butylborate, dichloromesityl-phenyl-methyl- or -butylborate, tris(dichloromesityl)-methylborate, tris(3-chlorphenyl)-hexylborate, tris(3-chlorphenyl)-methyl- or -butylborate, tris(3-bromphenyl)-hexylborate, tris(3-bromphenyl)-methyl- or -butylborate, tris(3,5-difluorphenyl)-hexylborate, dimesityl-biphenyl-butylborate, dimesityl-naphthylmethyl- or -butylborate, di(o-tolyl)-9-anthracyl-methyl- or -butylborate, dimesityl-9-phenanthryl-phenyl- or -butylborate
More preferably X is Clxe2x88x92, Brxe2x88x92, ClO4xe2x88x92, CF3SO3xe2x88x92, CH3SO3xe2x88x92, CF3COOxe2x88x92, BF4xe2x88x92, or PF6xe2x88x92.
Most preferably X is Brxe2x88x92.
Preferably n is 0.
In a preferred embodiment R1, R2, R3 are independently of each other unsubstituted C1-C18alkyl, C3-C18alkyl interrupted by at least one nitrogen or oxygen atom, C7-C9phenylalkyl, C3-C12cycloalkyl or C3-C12cycloalkyl containing at least one nitrogen or oxygen atom; or C1-C18alkyl, C3-C18alkyl interrupted by at least one nitrogen or oxygen atom, C7-C9phenylalkyl, C3-C12cycloalkyl or C3-C12cycloalkyl containing at least one nitrogen or oxygen atom, which are substituted by NO2, halogen, amino, hydroxy, cyano, carboxy, C1-C4alkoxy, C1-C4alkylthio, C1-C4alkylamino or di(C1-C4alkyl)amino; or
phenyl, which is unsubstituted or substituted by C1-C4alkyl, C1-C4alkoxy, C1-C4alkylthio, halogen, cyano, hydroxy, carboxy, C1-C4alkylamino or di(C1-C4alkyl)amino; or
R1 and R2, together with the linking hetero atom, form a C4-C7heterocycloalkyl radical; or
R1 and R2 form a group, 
or
xe2x80x83R1, R2 and R3 form a group 
More preferably R1, R2 and R3 independently of each other are unsubstituted C1-C12alkyl, C3-C12alkyl interrupted by at least one nitrogen or oxygen atom, benzyl or phenyl, which is unsubstituted or substituted by C1-C4alkyl, C1-C4alkoxy, C1-C4alkylthio, halogen, cyano, hydroxy, carboxy.
In a preferred subgroup of compounds of formula (Ia), (Ib) or (Ic) Y is CN, C(O)halogen, COOR4, phenyl which is unsubstituted or substituted by C1-C4alkyl, C1-C4alkoxy, C1-C4alkylthio, halogen, cyano, hydroxy, carboxy,
R4, is C1-C8alkyl;
X is Brxe2x88x92, ClO4xe2x88x92, CF3SO3xe2x88x92, CH3SO3xe2x88x92, CF3COOxe2x88x92, BF4xe2x88x92 or PF6xe2x88x92; and
R1, R2 and R3 independently of each other are unsubstituted C1-C12alkyl, C3-C12alkyl interrupted by at least one nitrogen or oxygen atom, benzyl or phenyl, which is unsubstituted or substituted by C1-C4alkyl, C1-C4alkoxy, C1-C4alkylthio, halogen, cyano, hydroxy, carboxy.
Preferred are compounds of formula (Ia).
Preferably the radical initiator b) is present in an amount of 0.01 to 5 weight % based on the monomer or monomer mixture.
Preferably the compound of formula (Ia), (Ib) or (Ic) is present in an amount of 0.01 to 10 weight % based on the monomer or monomer mixture.
The ratio of radical initiator to the compound of formula (Ia), (Ib) or (Ic) is preferably 0.1 to 10, more preferably 0.1 to 5 and most preferably 0.1 to 1.
The polymerization reaction may be carried out using photoinitiated radical polymerization. Photoinitiators useful in the present invention are of any known class. In certain cases it may be of advantage to use mixtures of two or more photoinitiators. Typical classes of photoinitators are for example camphor quinone, benzophenone, benzophenone derivatives, acetophenone, acetophenone derivatives, for example xcex1-hydroxycycloalkyl phenyl ketones or 2-hydroxy-2-methyl-1-phenyl-propanone, dialkoxyacetophenones, xcex1-hydroxy- or xcex1-amino-acetophenones, e.g. (4-methylthiobenzoyl)-1-methyl-1-morpholinoethane, (4-morpholinobenzoyl)-1-benzyl-1-dimethylaminopropane, 4-aroyl-1,3-dioxolanes, benzoin alkyl ethers and benzil ketals, e.g. dimethyl benzil ketal, phenylglyoxalic esters and derivatives thereof, dimeric phenylglyoxalic esters, peresters, e,g. benzophenone tetracarboxylic peresters as described for example in EP 126541, monoacyl phosphine oxides, e.g. (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, bisacylphosphine oxides, bis(2,6-dimethoxy-benzoyl)-(2,4,4-trimethyl-pentyl)phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4-dipentoxyphenylphosphine oxide, trisacylphosphine oxides, halomethyltriazines, e.g. 2-[2-(4-methoxy-phenyl)-vinyl]-4,6-bis-trichloromethyl-[1,3,5]triazine, 2-(4-methoxy-phenyl)-4,6-bis-trichloromethyl-[1,3,5]triazine, 2-(3,4-dimethoxy-phenyl)-4,6-bis-trichloromethyl-[1,3,5]triazine, 2-methyl-4,6-bis-trichloromethyl-[1,3,5]triazine, hexaarylbisimidazole/coinitiators systems, e.g. ortho-chlorohexaphenyl-bisimidazole combined with 2-mercaptobenzthiazole, ferrocenium compounds, or titanocenes, e.g. bis(cyclopentadienyl)-bis(2,6-difluoro-3-pyrryl-phenyl)titanium.
The photopolymerizable compositions generally comprise 0.05 to 15% by weight, preferably 0.1 to 5% by weight, of the photoinitiator, based on the composition. The amount refers to the sum of all photoinitiators added, if mixtures of initiators are employed.
Preferred compounds are of the xcex1-hydroxyketone type, phosphorus containing photoinitiators as well as the mixture of xcex1-hydroxyketone compounds with phosphorous containing photoinitiators.
Preferred photoinitiators are of the formula PI 
wherein
Ar is unsubstituted phenyl or phenyl substituted by halogen, CN, OH, C1-C17alkoxy, phenoxy, C2-C12alkenyl, xe2x80x94Sxe2x80x94C1-C12alkyl, xe2x80x94S-phenyl, xe2x80x94SO2xe2x80x94C1-C12alkyl, xe2x80x94SO2-phenyl, xe2x80x94SO2NH2, xe2x80x94SO2NHxe2x80x94C1-C12alkyl, xe2x80x94SO2xe2x80x94N(C1-C12-alkyl)2, xe2x80x94NHxe2x80x94C1-C12alkyl, xe2x80x94N(C1-C12alkyl)2 or xe2x80x94NHxe2x80x94CO-phenyl, isocyanate or masked isocyanate, or Ar is substituted with C1-C12alkyl, which C1-C12alkyl is unsubstituted or substituted by halogen, OH, CN, NH2, COOH, isocyanate, masked isocyanate, alkenyl or masked alkenyl, or Ar is thienyl, pyridyl, furyl, indanyl or tetrahydronaphthyl;
R101 is C1-C8alkyl, which is unsubstituted or substituted by OH, CN, NH2, xe2x80x94NHC1-C12alkyl, N(C1-C12alkyl)2, NHxe2x80x94CO-phenyl, isocyanate or masked isocyanate, C2-C12alkenyl, halogen, C1-C12alkoxy, COOH, xe2x80x94(CO)Oxe2x80x94C1-C12alkyl, xe2x80x94Oxe2x80x94(CO)xe2x80x94C1-C8alkyl or NR103R104, or R101 is C3-C5alkenyl, cyclopentyl, cyclohexyl or phenyl-C1-C3alkyl;
R102 has one of the meanings given for R101, or is a group xe2x80x94CH2CH2R5, or R102 together with R101 is C2-C8alkylene, C3-C9oxaalkylene, C3-C9azaalkylene, or an exomethylene cyclohexane ring, wherein the C2-C8alkylene, C3-C9oxaalkylene, C3-C9azaalkylene, or exomethylene cyclohexane ring is unsubstituted or substituted by OH, CN, halogen, C1-C12alkoxy, xe2x80x94(CO)Oxe2x80x94C1-C12alkyl, xe2x80x94Oxe2x80x94(CO)xe2x80x94C1-C8alkyl or NR103R104;
R103 is C1-C12alkyl, C2-C4alkyl which is substituted by OH, C1-C8alkoxy or CN, or R103 is C3-C5alkenyl, cyclohexyl, phenyl-C1-C3alkyl, unsubstituted phenyl or phenyl, which is substituted by Cl, C1-C4alkyl, OH, C1-C4alkoxy or xe2x80x94(CO)Oxe2x80x94C1-C8alkyl;
R104 is C1-C12alkyl, C2-C4alkyl which is substituted by OH, C1-C8alkoxy or CN, or R104 is C3-C5alkenyl, cyclohexyl or phenyl-C1-C3alkyl, or R104 together with R103 is C4-C5alkylene, which may be interrupted by xe2x80x94Oxe2x80x94 or xe2x80x94NR106xe2x80x94, or R104 together with R102 is C1-C9alkylene, C2-C3oxaalkylene or C2-C3azaalkylene;
R105 is xe2x80x94COxe2x80x94NH2, xe2x80x94COxe2x80x94NHxe2x80x94C1-C8alkyl, xe2x80x94COxe2x80x94N(C1-C8alkyl)2, xe2x80x94P(O)(Oxe2x80x94C1-C8alkyl)2 2-pyrridyl or 2-oxo-1-pyrroldinyl; and
R106 is C1-C4alkyl, xe2x80x94CH2CH2CN or xe2x80x94CH2CH2(CO)Oxe2x80x94C1-C8alkyl.
C1-C17alkoxy is linear or branched and is for example C1-C12alkoxy, C1-C8- or C1-C6alkoxy, especially C1-C4alkoxy. Examples are methoxy, ethoxy, propoxy, isopropoxy, n-butyloxy, sec-butyloxy, iso-butyloxy, tert-butyloxy, pentyloxy, hexyloxy, heptyloxy, 2,4,4-trimethylpentyloxy, 2-ethylhexyloxy, octyloxy, nonyloxy, decyloxy, dodecyloxy, tetradecyloxy, pentadecyloxy, hexadecyloxy or heptadecyloxy especially methoxy, ethoxy, propoxy, isopropoxy, n-butyloxy, sec-butyloxy, iso-butyloxy, tert-butyloxy, preferably methoxy. C1-C12alkoxy, C1-C8alkoxy and C1-C4alkoxy have the same meanings as given above up to the appropriate number of C-atoms.
C2-C12alkenyl is one or more times unsaturated and is for example C2-C8-alkenyl, C2-C6- or C3-C5-alkenyl, especially C2-C4-alkenyl. Examples are allyl, methallyl, 1,1-dimethylallyl, 1-butenyl, 3-butenyl, 2-butenyl, 1,3-pentadienyl, 5-hexenyl, 7-octenyl, nonenyl, dodecenyl, especially allyl. C3-C5alkenyl has the same meanings as given above up to the appropriate number of C-atoms.
C1-C12alkyl is linear or branched and is for example C1-C10-, C1-C8- or C1-C6alkyl, especially C1-C4alkyl. Examples are methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, iso-butyl, tert-butyl, pentyl, hexyl, heptyl, 2,4,4-trimethyl-pentyl, 2-ethylhexyl, octyl, nonyl, decyl, undecyl or dodecyl, preferably methyl or butyl. C1-C8alkyl and C2-C4alkyl have the same meanings as given above up to the appropriate number of C-atoms. In the terms xe2x80x94Sxe2x80x94C1-C12alkyl, xe2x80x94SO2xe2x80x94C1-C12alkyl, xe2x80x94COOxe2x80x94C1-C12alkyl, xe2x80x94SO2NHxe2x80x94C1-C12alkyl, xe2x80x94SO2xe2x80x94N(C1-C12-alkyl)2, xe2x80x94NHxe2x80x94C1-C12alkyl and xe2x80x94N(C1-C12alkyl)2, C1-C12alkyl has the meanings given above. In the groups xe2x80x94Oxe2x80x94(CO)xe2x80x94C1-C8alkyl, xe2x80x94COxe2x80x94NHxe2x80x94C1-C8alkyl, xe2x80x94COxe2x80x94N(C1-C8alkyl)2, xe2x80x94CH2CH2(CO)Oxe2x80x94C1-C8alkyl and xe2x80x94P(O)(Oxe2x80x94C1-C8alkyl)2 C1-C8alkyl has the same meanings as given above. If C1-C12alkyl is substituted with halogen, there are, for example 1 to 3 or 1 or 2 halogen substituents located at the alkyl.
The term xe2x80x9cmasked isocyanatexe2x80x9d means a protected isocyanate group, namely an isocyanate group, which is blocked by chemical groups, which under specific reaction conditions can be removed. So, the formation of an oxime results in a masked isocyanate group. Examples are given, for example in J. Coatings Technology, Vol. 61, No. 775 (August 1989). The blocking/deblocking mechanism is, for example, demonstrated by the following equation: Rxe2x80x94Nxe2x80x94(CO)xe2x80x94X (blocked isocyanate)⇄Rxe2x80x94Nxe2x95x90Cxe2x95x90O+HX On the left side the blocked isocyanate is not susceptible to reactions in the formulation, while on the right side the influence of temperature ( greater than 120xc2x0 C.) deblocks HX and liberates the isocyanate group, which is now able to take part in further reactions, for example with crosslinkers. Suitable blocking agents HX are, for example, phenol, caprolactam, methyl ethyl ketoxime and diethyl malonate.
Phenyl-C1-C3alkyl is, for example, benzyl, phenylethyl, xcex1-methylbenzyl, Phenylpropyl, or xcex1,xcex1-dimethylbenzyl, especially benzyl.
C2-C8alkylene is linear or branched alkylene as, for example, methylene, ethylene, propylene, 1-methylethylene, 1,1-dimethylethylene, butylene, 1-methylpropylene, 2-methylpropylene, pentylene, hexylene, heptylene or octylene, especially hexylene. C4-C5alkylene is linear or branched, for example, 1,1-dimethylethylene, butylene, 1-methylpropylene, 2-methylpropylene or pentylene. C4-C5alkylene, which may be interrupted by xe2x80x94Oxe2x80x94 or xe2x80x94NR106xe2x80x94, is, for example, xe2x80x94CH2CH2xe2x80x94Oxe2x80x94CH2CH2xe2x80x94, xe2x80x94CH2CH2xe2x80x94(NR106)xe2x80x94CH2CH2xe2x80x94, xe2x80x94CH2xe2x80x94Oxe2x80x94CH2CH2CH2xe2x80x94, xe2x80x94CH2xe2x80x94(NR106)xe2x80x94CH2CH2CH2xe2x80x94 or xe2x80x94CH2CH2xe2x80x94Oxe2x80x94CH2CH2CH2xe2x80x94. C3-C9oxaalkylene can contain, for example, 1-3 or 1 or 2 O-atoms, especially 1 O-atom and means for example, xe2x80x94CH2xe2x80x94Oxe2x80x94CH2xe2x80x94, xe2x80x94CH2CH2Oxe2x80x94CH2CH2xe2x80x94, xe2x80x94CH2xe2x80x94CH(CH3)xe2x80x94Oxe2x80x94CH2CH2CH2xe2x80x94 or xe2x80x94[CH2CH2O]y, wherein y=1-4. C3-C9azaalkylene can contain, for example, 1-3 or 1 or 2 (NR106)-groups, especially 1 such group and means, for example, xe2x80x94CH2xe2x80x94(NR106)xe2x80x94CH2xe2x80x94, xe2x80x94CH2CH2xe2x80x94(NR106)xe2x80x94CH2CH2xe2x80x94, xe2x80x94CH2xe2x80x94CH(CH3)xe2x80x94(NR106)xe2x80x94CH2CH2CH2xe2x80x94 or xe2x80x94[CH2CH2(NR106)]y wherein y=1-4 and wherein R106 has the meanings given above.
The exomethylen cyclohexane ring has the following structure 
Halogen is fluorine, chlorine, bromine and iodine, especially chlorine and bromine, preferably chlorine.
Preferably Ar in the formula I is unsubstituted phenyl or phenyl substituted by C1-C12alkyl or phenyl substituted by C1-C4alkyl, which is substituted with OH, R101 and R102 are C1-C4alkyl, or R102 together with R101 and the C-atom to which they are bonded, are C2-C8alkylene.
Suitable compounds of the formula I are
phenyl-1-hydroxycyclohexylketone ((copyright)Irgacure 184; Ciba-Geigy AG);
4-dodecylphenyl-2-hydroxy-prop-2-yl ketone;
4-isopropylphenyl-2-hydroxy-prop-2-yl ketone;
2-hydroxy-2-methyl-1-phenyl-propanone;
[4-(2-hydroxyethyl)-phenyl]-2-hydroxy-prop-2-yl ketone;
4-methylphenyl-2-hydroxy-prop-2-yl ketone
[4-(2-carboxyethyl)-phenyl]-2-hydroxy-prop-2-yl ketone.
Especially preferred are phenyl-1-hydroxycyclohexylketone, 2-hydroxy-2-methyl-1-phenyl-propanone, [4-(2-hydroxyethyl)-phenyl]-2-hydroxy-prop-2-yl ketone and [4-(2-carboxyethyl)-phenyl]-2-hydroxy-prop-2-yl ketone. The photoinitators according to the formula I are known, some of the compounds are commercially available and the art-skilled is familiar with their preparation. The compounds and their preparation are, for example, disclosed in U.S. Pat. Nos. 4,308,400; 4,315,807; 4,318,791; 4,721,734; 4,347,111; 4,477,681; 4,861,916; 5,045,573.
Preferred is also a mixture of photoinitiators of at least one compound of the formula I and at least one phosphorus containing photoinitator of the formula IIa or IIb 
wherein
R107 and R108 independently of one another are C1-C18alkyl, cyclohexyl, cyclopentyl, phenyl, naphthyl or biphenyl, wherein the cyclohexyl, cyclopentyl, phenyl, naphthyl or biphenyl are unsubstituted or substituted by halogen, C1-C12alkyl and/or C1-C12alkoxy, or R7 and R8 are a 5- or 6-membered S- or N-containing heterocyclic ring;
R109 and R110 independently of one another are cyclohexyl, cyclopentyl, phenyl, naphthyl or biphenyl, which residues are unsubstituted or substituted by halogen, C1-C4alkyl and/or C1-C4alkoxy, or R109 and R110 are a 5- or 6-membered S- or N-containing heterocyclic ring, or R109 and R110 together with the P-atom to which they are bonded from a ring, which contains from 4 to 10 carbon atoms and which ring may be substituted by 1 to 6 C1-C4alkyl radicals.
C1-C18Alkyl is branched or unbranched alkyl and is, for example, C1-C12-, C1-C10-, C1-C8- or C1-C6-alkyl, especially C1-C4alkyl. Examples are methyl, ethyl, propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, 2,4,4-trimethyl-pentyl, decyl, dodecyl, tetradecyl, heptadecyl or octadecyl. C1-C12alkyl has the same meanings as given above up to the appropriate number of C-atoms
Preferably R108 as alkyl is C4-C8alkyl, for example n-butyl, tert-butyl, isobutyl, sec-butyl, n-octyl, 2,4,4-trimethylpentyl.
C1-C12alkoxy is linear or branched and is for example C1-C8- or C1-C6alkoxy, especially C1-C4alkoxy. Examples are methoxy, ethoxy, propoxy, isopropoxy, n-butyloxy, sec-butyloxy, iso-butyloxy, tert-butyloxy, pentyloxy, hexyloxy, heptyloxy, 2,4,4-trimethylpentyloxy, 2-ethylhexyloxy, octyloxy, nonyloxy, decyloxy or dodecyloxy, especially methoxy, ethoxy, propoxy, isopropoxy, n-butyloxy, sec-butyloxy, iso-butyloxy, tert-butyloxy, preferably methoxy.
Halogen is fluorine, chlorine, bromine and iodine, especially chlorine and bromine, preferably chlorine.
Naphthyl means xcex1-naphthyl and xcex2-naphthyl.
Substituted cyclopentyl, cyclohexyl, phenyl, naphthyl or biphenyl have, for example 1-5, 1-4, three, two or one substituents. For substituted phenyl the substitution in 4-, 2,5-, 2-, 2,6- or 2,4,6-position is preferred. Examples for such groups are 4-chlorophenyl, 2,6-dichlorophenyl, 2,4,6-trichlorophenyl, difluorophenyl, 2-tolyl, 4-tolyl, ethylphenyl, tert-butylphenyl, dodecylphenyl, 4-methoxyphenyl, 2-methoxyphenyl, 2,6-dimethoxyphenyl, ethoxyphenyl, hexyloxyphenyl, 2,4-dimethylphenyl, 2,4,6-trimethylphenyl, methylnaphthyl, isopropylnaphthyl, chloronaphthyl or ethoxynaphthyl. Furthermore, such groups are, for example, methoxyethylphenyl, ethoxymethylphenyl.
R109 and R110 preferably are substituted phenyl, for example 2,6-dimethoxyphenyl, 2,6-dichlorphenyl, 2,4,6-trimethylphenyl, especially 2,4,6-trimethylphenyl. A 5- or 6-membered S- or N-containing heterocyclic ring is, for example, thienyl, pyrryl, pyrazolyl, thiazolyl, pyridyl or 1,3-, 1,2- or 1,4-diazyl, preferably thienyl or pyrryl.
If R109 and R110 together with the P-atom to which they are bonded form a ring containing 4 to 10 C-atoms this ring is monocyclic, bicyclic or tricyclic. A monocyclic ring formed by R109 and R110 together with the P-atom is preferably a phosphacyclopentane ring. A bicyclic ring formed by R109 and R110 together with the P-atom is preferably a phosphabicyclohexane or phosphabicyclononane ring. A tricyclic ring formed by R109 and R110 together with the P atom is preferably a (6H)-dibenzo[c,e][1,2]oxaphosphorine ring.
R109 and R110 are preferably 2,6-dimethoxyphenyl, 2,6-dimethylphenyl, 2,6-dichlorophenyl or especially 2,4,6-trimethylphenyl.
R107 and R108 preferably are C1-C18alkyl, cyclohexyl, cyclopentyl, phenyl or phenyl substituted with C1-C4alkyl. Specifically preferred R107 and R108 are n-butyl, tert-butyl, isobutyl, sec-butyl, n-octyl, 2,4,4-trimethylpentyl, phenyl or 2,5-dimethylphenyl.
The photoinitators according to the formulae IIa and IIb are known, some are commercially available compounds and the art-skilled is familiar with their preparation. The compounds and their preparation are, for example, disclosed in U.S. Pat. Nos. 4,792,632; 4,737,593; 4,298,738; 5,218,009; 5,399,770; 5,472,992.
Suitable compounds of the formula IIa and IIb are
2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide;
bis(2,4,6-trimethylbenzoyl)-2,4-di(3-methyl-but-1-oxy)phenyl-hosphine oxide;
bis(2,4,6-trimethylbenzoyl)-2,4-dipentoxyphenyl-phosphine oxide;
bis(2,4,6-trimethylbenzoyl)-2-methyl-prop-1-yl-phosphine oxide;
bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpent-1-yl-phosphine oxide;
bis(2,4,6-trimethylbenzoyl)-phenyl phosphine oxide;
Examples for photoinitiator mixtures suitable for the instant processes are
a mixture of bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpent-1-yl-phosphine oxide with 2-hydroxy-2-methyl-1-phenyl-propanone;
a mixture of 2-hydroxy-2-methyl-1-phenyl-propanone with (2,4,6-trimethylbenzoyl)-diphenyl phosphine oxide;
a mixture of phenyl-1-hydroxycyclohexylketone with bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpent-1-yl-phosphine oxide;
a mixture of phenyl-1-hydroxycyclohexylketone with bis(2,4,6-trimethylbenzoyl)-2-methyl-prop-1-yl-phosphine oxide;
a mixture of phenyl-1-hydroxycyclohexylketone with bis(2,4,6-trimethylbenzoyl)-phenyl phosphine oxide;
a mixture of phenyl-1-hydroxycyclohexylketone with bis(2,4,6-trimethylbenzoyl)-2,4-dipentoxyphenyl-phosphine oxide;
a mixture of 2-hydroxy-2-methyl-1-phenyl-propanone with bis(2,4,6-trimethylbenzoyl)-2-methyl-prop-1-yl-phosphine oxide;
a mixture of 2-hydroxy-2-methyl-1-phenyl-propanone with bis(2,4,6-trimethylbenzoyl)-phenyl phosphine oxide;
a mixture of 2-hydroxy-2-methyl-1-phenyl-propanone with bis(2,4,6-trimethylbenzoyl)-2,4-dipentoxyphenyl-phosphine oxide.
The range of the xcex1-hydroxyketone photoinitiator, compounds of the formula PI respectively, in the mixtures of these compounds with phosphorus containing photoinitiators, compounds of the formula IIa or IIb respectively, is, for example 50-95% by weight. Preferably the amount of the compounds of the formula I in the mixture is 50-75%, especially 75% (based on 100% by weight of the total mixture).
Of interest is a process, wherein the formula PI Ar is unsubstituted phenyl or phenyl substituted by C1-C12alkyl, which C1-C12alkyl is unsubstituted or substituted by OH or COOH, R101 and R102 are C1-C18alkyl or R101 together with R102 is C2-C8alkylene, and wherein the formula IIa or the formula IIb R107 and R108 independently of one another are C1-C12alkyl or phenyl, wherein the phenyl is unsubstituted or substituted by C1-C8alkyl and/or C1-C8alkoxy and R109 and R110 independently of one another are phenyl, which is substituted by halogen, C1-C4alkyl and/or C1-C4alkoxy.
Preferred is, for example, a mixture of 2-hydroxy-2methyl-1-phenyl-propanone with bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpent-1-yl-phosphine oxide. Especially preferred is the above mixture with an amount of 2-hydroxy-2methyl-1-phenyl-propanone of 75% by weight.
Also preferred, for example, is a mixture of 2-hydroxy-2methyl-1-phenyl-propanone with 2,4,6-trimethylbenzoyl-phenyl-phosphine oxide. Especially preferred is the above mixture with an amount of 2-hydroxy-2methyl-1-phenyl-propanone of 50% by weight.
The composition to be (co)polymerized in the instant process expediently contains the photoinitiator of the formula PI, IIa or IIb, or the photoinitiator mixture of the compounds of the formulae I and IIa or IIb in an amount of from 0.1 to 15% by weight, preferably from 0.2 to 5% by weight, based on the total solids content.
Additional coinitiators or sensitizers may be used. These are typically dyes which react by energy transfer or electron transfer and such enhance the overall quantum yield. Typical dyes are for example triarylmethane, such as malachit green, indoline, thiazine, such as methylen blue, xanthone, thioxanthone, oxazine, acridine or phenazine, such as safranine, or rhodamine of formula 
wherein R is alkyl or aryl and Rxe2x80x2 is hydrogen, alkyl or aryl. Examples are Rhodamin B, Rhodamin 6G oder Violamin R, Sulforhodamin B or Sulforhodamin G.
Preferred are thioxanthone, oxazine, acridine, phenazine or rhodamine. The polymerization reaction may also be carried out using thermally initiated radical polymerization. The source of radicals may be a bis-azo compound, a peroxide or a hydroperoxide.
Most preferably, the source of radicals is 2,2xe2x80x2-azobisisobutyronitrile, 2,2xe2x80x2-azobis(2-methylbutyronitrile), 2,2xe2x80x2-azobis(2,4-dimethylvaleronitrile), 2,2xe2x80x2-azobis(4-methoxy-2,4-dimethylvaleronitrile), 1,1xe2x80x2-azobis(-cyclohexanecarbonitrile), 2,2xe2x80x2-azobis(isobutyramide)dihydrate, 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, dimethyl-2,2xe2x80x2-azobisisobutyrate, 2-(carbamoylazo)isobutyronitrile, 2,2xe2x80x2-azobis(2,4,4-trimethylpentane), 2,2xe2x80x2-azobis(2-methylpropane), 2,2xe2x80x2-azobis(N,Nxe2x80x2-dimethyleneisobutyramidine), free base or hydrochloride, 2,2xe2x80x2-azobis(2-amidinopropane), free base or hydrochloride, 2,2xe2x80x2-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)ethyl]propionamide} or 2,2xe2x80x2-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide. Preferred peroxides and hydroperoxides are acetyl cyclohexane sulphonyl peroxide, diisopropyl peroxy dicarbonate, t-amyl perneodecanoate, t-butyl perneodecanoate, t-butyl perpivalate, t-amylperpivalate, bis(2,4-dichlorobenzoyl)peroxide, diisononanoyl peroxide, didecanoyl peroxide, dioctanoyl peroxide, dilauroyl peroxide, bis (2-methylbenzoyl)peroxide, disuccinic acid peroxide, diacetyl peroxide, dibenzoyl peroxide, t-butyl per 2-ethylhexanoate, bis-(4-chlorobenzoyl)-peroxide, t-butyl perisobutyrate, t-butyl permaleinate, 1,1-bis(t-butylperoxy)3,5,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, t-butyl peroxy isopropyl carbonate, t-butyl perisononaoate, 2,5-dimethylhexane 2,5-dibenzoate, t-butyl peracetate, t-amyl perbenzoate, t-butyl perbenzoate, 2,2-bis(t-butylperoxy)butane, 2,2bis (t-butylperoxy)propane, dicumyl peroxide, 2,5-dimethylhexane-2,5-di-t-butylperocide, 3-t-butylperoxy 3-phenylphthalide, di-t-amyl peroxide, xcex1,xcex1xe2x80x2-bis(t-butylperoxy isopropyl)benzene, 3,5-bis(t-butylperoxy)3,5-dimethyl 1,2-dioxolane, di-t-butyl peroxide, 2,5-dimethylhexyne-2,5-di-t-butylperoxide, 3,3,6,6,9,9-hexamethyl 1,2,4,5-tetraoxa cyclononane, p-menthane hydroperoxide, pinane hydroperoxide, diisopropylbenzene mono-xcex1-hydroperoxide, cumene hydroperoxide or t-butyl hydroperoxide.
These compounds are commercially available.
Typically the ethylenically unsaturated monomer or oligomer is selected from the group consisting of ethylene, propylene, n-butylene, i-butylene, styrene, substituted styrene, conjugated dienes, acrolein, vinyl acetate, vinylpyrrolidone, vinylimidazole, maleic anhydride, (alkyl)acrylic acidanhydrides, (alkyl)acrylic acid salts, (alkyl)acrylic esters, (meth)acrylonitriles, (alkyl)acrylamides, vinyl halides or vinylidene halides. Preferred ethylenically unsaturated monomers are ethylene, propylene, n-butylene, i-butylene, isoprene, 1,3-butadiene, xcex1-C5-C18alkene, styrene, xcex1-methyl styrene , p-methyl styrene or a compound of formula CH2xe2x95x90C(Ra)xe2x80x94(Cxe2x95x90Z)xe2x80x94Rb, where in Ra is hydrogen or C1-C4alkyl, Rb is NH2, Oxe2x88x92(Me+), glycidyl, unsubstituted C1-C18alkoxy, C2-C100alkoxy interrupted by at least one N and/or O atom, or hydroxy-substituted C1-C18alkoxy, unsubstituted C1-C18alkylamino, di(C1-C18alkyl)amino, hydroxy-substituted C1-C18alkylamino or hydroxy-substituted di(C1-C18alkyl)amino, xe2x80x94Oxe2x80x94CH2xe2x80x94CH2xe2x80x94N(CH3)2 or xe2x80x94Oxe2x80x94CH2xe2x80x94CH2xe2x80x94N+H(CH3)2Anxe2x88x92; Anxe2x88x92 is a anion of a monovalent organic or inorganic acid; Me is a monovalent metal atom or the ammonium ion. Z is oxygen or sulfur.
Examples for Ra as C2-C100alkoxy interrupted by at least one O atom are of formula 
wherein Rc is C1-C25alkyl, phenyl or phenyl substituted by C1-C18alkyl, Rd is hydrogen or methyl and v is a number from 1 to 50. These monomers are for example derived from non ionic surfactants by acrylation of the corresponding alkoxylated alcohols or phenols. The repeating units may be derived from ethylene oxide, propylene oxide or mixtures of both.
Further examples of suitable acrylate or methacrylate monomers are given below. 
An- or 
Anxe2x88x92, wherein Anxe2x88x92 and Ra have the meaning as defined above and Re is methyl or benzyl. Anxe2x88x92 is preferably Clxe2x88x92, Brxe2x88x92 or xe2x88x92O3Sxe2x80x94CH3.
Further acrylate monomers are 
Examples for suitable monomers other than acrylates are 
Preferably Ra is hydrogen or methyl, Rb is NH2, gycidyl, unsubstituted or with hydroxy substituted C1-C4alkoxy, unsubstituted C1-C4alkylamino, di(C1-C4alkyl)amino, hydroxy-substituted C1-C4alkylamino or hydroxy-substituted di(C1-C4alkyl)amino; and Z is oxygen.
Particularly preferred ethylenically unsaturated monomers are styrene, methylacrylate, ethylacrylate, butylacrylate, isobutylacrylate, tert. butylacrylate, hydroxyethylacrylate, hydroxypropylacrylate, dimethylaminoethylacrylate, glycidylacrylates, methyl(meth)acrylate, ethyl(meth)acrylate, butyl(meth)acrylate, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, dimethylaminoethyl(meth)acrylate, glycidyl(meth)acrylates, acrylonitrile, acrylamide, methacrylamide or dimethylaminopropyl-methacrylamide.
Another subject of the present invention is a process for preparing an oligomer, a cooligomer, a polymer or a copolymer (block or random) by free radical polymerization of
a) at least one ethylenically unsaturated monomer or oligomer, which comprises (co)polymerizing the monomer or monomers/oligomers in the presence of
b) a radical initiator which forms a radical upon heating or upon irradiation with (UV) light from 305 nm to 450 nm and
c) a compound of formula (Ia), (Ib) or (Ic) according to claim 1 by subjecting the mixture to heat or electromagnetic radiation in the wavelength range from 305 nm to 450 nm.
Definitions and preferences for the different substituents have already been given and apply also for the polymerization process.
Preferably the radical initiator b) is present in an amount of 0.01 to 5 weight % based on the monomer or monomer mixture.
Preferably the compound of formula (Ia), (Ib) or (Ic) is present in an amount of 0.01 to 10 weight % based on the monomer or monomer mixture.
The ratio of radical initiator to the compound of formula (Ia), (Ib) or (Ic) is preferably 0.1 to 10, more preferably 0.1 to 5 and most preferably 0.1 to 1.
The process may be carried out in the presence of an organic solvent or in the presence of water or in mixtures of organic solvents and water. Additional cosolvents or surfactants, such as glycols or ammonium salts of fatty acids, may be present. Other suitable cosolvents are described hereinafter.
Preferred processes use as little solvents as possible. In the reaction mixture it is preferred to use more than 30% by weight of monomer and initiator, particularly preferably more than 50% and most preferrably more than 80%. In many cases it is possible to polymerize without any solvent, particularly if the process is carried out by photo initiated radical polymerization.
If organic solvents are used, suitable solvents or mixtures of solvents are typically pure alkanes (hexane, heptane, octane, isooctane), hydrocarbons (benzene, toluene, xylene), halogenated hydrocarbons (chlorobenzene), alkanols (methanol, ethanol, ethylene glycol, ethylene glycol monomethyl ether), esters (ethyl acetate, propyl, butyl or hexyl acetate) and ethers (diethyl ether, dibutyl ether, ethylene glycol dimethyl ether), or mixtures thereof.
Aqueous polymerization reactions can be supplemented with a water-miscible or hydrophilic cosolvent to help ensure that the reaction mixture remains a homogeneous single phase throughout the monomer conversion. Any water-soluble or water-miscible cosolvent may be used, as long as the aqueous solvent medium is effective in providing a solvent system which prevents precipitation or phase separation of the reactants or polymer products until after all polymerization reactions have been completed. Exemplary cosolvents useful in the present invention may be selected from the group consisting of aliphatic alcohols, glycols, ethers, glycol ethers, pyrrolidines, N-alkyl pyrrolidinones, N-alkyl pyrrolidones, polyethylene glycols, polypropylene glycols, amides, carboxylic acids and salts thereof, esters, organosulfides, sulfoxides, sulfones, alcohol derivatives, hydroxyether derivatives such as butyl carbitol or cellosolve, amino alcohols, ketones, and the like, as well as derivatives thereof and mixtures thereof. Specific examples include methanol, ethanol, propanol, dioxane, ethylene glycol, propylene glycol, diethylene glycol, glycerol, dipropylene glycol, tetrahydrofuran, and other water-soluble or water-miscible materials, and mixtures thereof. When mixtures of water and water-soluble or water-miscible organic liquids are selected as the aqueous reaction media, the water to cosolvent weight ratio is typically in the range of about 100:0 to about 10:90.
The oligomers/polymers prepared with the instant process can be used for various purposes, for example for the production of printing inks, varnishes, white paints, coating compositions, inter alia for paper, wood, metal or plastic, for the production of coloured pigmented paints, daylight-curable coatings for buildings and road markings, for the preparation of clear or pigmented aqueous dispersions, for the production of printing plates, for the production of masks for screen printing, as dental filling materials, for the production of adhesives, of etch or permanent resists and of solder stop masks for printed electronic circuits, for the production of three-dimensional articles by bulk curing (UV curing in transparent moulds) or for the production of formulations used in the stereolithography process, as described, for example, in U.S. Pat. No. 4,575,330, for the preparation of composite materials (for example styrenic polyesters, which may contain glass fibres and other assistants) and other thick-layer compositions, for the production of coatings for encapsulation of electronic parts or for the production of coatings for optical fibres.
A further subject of the present invention is a polymer or copolymer prepared by the above process containing a vinyl- or 1,3 dienyl group at one end of the molecule. Preferably the polymers have an average number molecular weight (Mn) of 1000-500 000 more preferably 5000-300 000, and most preferably 5000-100 000.
The polydispersity (PD) as defined by Mn/Mw is preferably below 3, more preferably from 1.1 to 2.5 and most preferably from 1.1 to 2.
The chain transfer coefficient cx is preferably from 0.4 to 1, more preferably from 0.6 to 1 and most preferably from 0.7 to 1.
The thermally initiated reaction may be carried out in any vessel suitable for radical polymerization reactions. Examples are known in the art.
Preferably the reaction temperature is kept between 60xc2x0 C. and 120xc2x0 C. Reaction time may vary, depending on the molecular weight desired. Typical reaction times are from 1 hour to 24 hours.
Photochemically initiated radical polymerization may be carried out for example in an apparatus as described in WO 98/37105.
The photoreactor used to prepare the examples is fabricated in Rodoxal, an aluminum alloy, but suitable reactors can also be constructed, for example in stainless steel or in any material compatible with the monomers employed, as for example teflon, brown glass etc. The reactor possesses a glass window allowing transmission of the UV-light. The overall irradiation surface of the reactor is 26 cm2 and the cell thickness is 1 cm. In this connection the xe2x80x9coverall irradiation surfacexe2x80x9d of the reactor means the surface of the irradiated part of the reactor, namely the window and the xe2x80x9ccell thicknessxe2x80x9d is the thickness of the internal path (diameter) of the reactor at the irradiated part. The process can also be carried out using an optical bench and a UV-cell for absorption spectra fitted with a septum to allow reactions under argon and a magnetic stirrer. This UV-cell, similar to those used to measure UV-spectra, may be irradiated through a 2 cm2 window with homogeneous light from a Philips 100 W medium pressure mercury lamp and the cooling may be effected through the side walls of the cell. Bigger reactor dimensions, as for example an overall irradiation surface (window size) of 26 cm2 with a cell thickness (diameter) of 1 cm need lamps of higher output and bigger. irradiation surfaces such as, for example, Fusion Curing lamps F200 to F600. As those commercially available lamps have a bulb length of 6 inches (about 15.5 cm; F200 lamp) or 10 inches (about 25 cm; F600 lamp), the reactor should not exceed this height. The irradiation surface can thus be adapted to the necessary reaction conditions. Naturally, for the instant process it is also possible to employ reactors with other dimensions. The crucial point is to guarantee a controlable and homogenic generation of radicals of the photoinitiator throughout the reactor, which is achieved, by controling the flow of the mixture and the distribution of radicals in the mixture by stirring and appropriate irradiation. This is not dependent on the size of the reactor or the irradiation surface.
The reaction time depends on the intensity of the UV-lamp, the area of irradiation, monomer and initiator concentration and may thus vary in a very wide range, depending on the conditions actually used.
The reaction temperature of the photochemically induced polymerization is preferably kept between 20xc2x0 and 70xc2x0 C. The reaction time is preferably from 5 minutes to 5 hours, more preferably from 10 minutes to 2 hours.
A further subject of the present invention is the use of a compound of formulae (Ia), (Ib) or (Ic) according to claim 1 in a radical initiated polymerization process.
Yet another subject of the invention are new compounds according to formula (Xa), (Xb) or (Xc) 
wherein
Y is CN, C(O)halogen, COOR4, C(O)R4, CONR5R6, phenyl or naphthyl which are unsubstituted or substituted by C1-C4alkyl, C1-C4alkoxy, C1-C4alkylthio, halogen, nitro, cyano, hydroxy, carboxy, C1-C4alkylamino or di(C1-C4alkyl)amino; and
R4, R5 and R6 are hydrogen or C1-C18alkyl;
X is Clxe2x88x92, Brxe2x88x92, xe2x80x94Ixe2x88x92, ClO4xe2x88x92, CF3SO3xe2x88x92, CH3SO3xe2x88x92, CF3COOxe2x88x92, p-toluene sulfonate, HSO4xe2x88x92, BF4xe2x88x92, PF6xe2x88x92, SbCl6xe2x88x92, AsF6xe2x88x92, SbF6xe2x88x92 or a mono carboxylic acid from 1-12 carbon atoms;
n is 0 or 1;
R1, R2 R3 are independently of each other hydrogen, unsubstituted C1-C18alkyl, C3-C18alkyl, interrupted by at least one nitrogen or oxygen atom, C3-C18alkenyl, C3-C18alkynyl, C7-C9phenylalkyl, C3-C12cycloalkyl or C3-C12cycloalkyl containing at least one nitrogen or oxygen atom; or
C3-C18alkyl, C3-C18alkyl, interrupted by at least one nitrogen or oxygen atom, C3-C18alkenyl, C3-C18alkynyl, C7-C9phenylalkyl, C3-C12cycloalkyl or C3-C12cycloalkyl containing at least one nitrogen or oxygen atom, which are substituted by NO2, halogen, amino, hydroxy, cyano, carboxy, C1-C4alkoxy, C1-C4alkylthio, C1-C4alkylamino, di(C1-C4alkyl)amino or by a group xe2x80x94Oxe2x80x94C(O)xe2x80x94C1-C18alkyl; or
phenyl, naphthyl, which are unsubstituted or substituted by C1-C4alkyl, C1-C4alkoxy, C1-C4alkylthio, halogen, cyano, hydroxy, carboxy, C1-C4alkylamino or di(C1-C4alkyl)amino; or
R1 and R2, together with the linking hetero atom, form a C3-C12 heterocycloalkyl radical; or
R1 and R2 form a group, 
xe2x80x83or
R1, R2 and R3 form a group 
R10 and R20 are independently of each other C3-C18alkyl which is unsubstituted or substituted by NO2, halogen, amino, hydroxy, cyano, carboxy, C1-C4alkoxy, C1-C4alkylthio, C1-C4alkylamino or di(C1-C4alkyl)amino; and
R30 is hydrogen or methyl.
Preferred are compounds of formula (Xa), wherein Y is phenyl, CN or COOR4 and R4 is C1-C4alkyl.
Preferably in the compounds of formula (Xa) X is Cl or Br.
Preferably in the compounds of formula (Xa) R2 and R3 are C6-C12alkyl.
The compounds of formula (Ia), (Ib), (Ic), X(a), X(b) and X(c) can be prepared according to known methods.
An analogous synthesis is for example described in U.S. Pat. No. 4,247,700 as well as in CA: 96 163229c. The synthesis of the acrylic and acrylonitrile derivatives is effected by Mannich reaction of the aliphatic amine with cyanacetic acid or monoesters of malonic acid in the presence of formaldehyde solutions in water, followed by reaction with an alkylating agent. The styrene equivalent is best synthesized in analogy to WO88/04304 starting from xcex1-brommethyl styrene and the corresponding amine. Another possibility is described by in Melikyan et al. in Chemistry Papers 46 (4), 269-271 (1992) starting from the corresponding cinnamates.